Metric. 4-piece set. Incl. 4 wrenches with an open end on one side and a ratcheting box end on the other side, with identical sizes on both ends. Packed in a robust textile pouch with hook and loop on the rear side. Color coded for size. When everything fails, it's time to play your Joker. - Open end. The Joker has a non-angled 12-point beak, therefore it requires just 30° of working space, otherwise it functions just like a regular open end wrench. The dark metal plate dual functions as a retainer, preventing the nut to slip through the wrench beak or it holds the nut. 30° further the metal retainer plate allows the nut to slide through, or grip it since the metal plate is equipped with a hardened ragged edge. The teeth of this edge will 'bite' itself into a rounded-off nut, loosening it where others do nothing but slip-off. - Box end. The box end head is angled at 15° from the handle. Comes with a switch for ratcheting direction and a very fine 80 tooth ratchet for a small 4.5° return angle. Set includes: Size: 10mm Overall length: 159mm. Size: 13mm Overall length: 177mm. Size: 17mm Overall length: 224mm. Size: 19mm Overall length: 246mm.